黑河流域植物物种多样性对土地利用变化的响应北大核心CSCD

黑河流域土地利用变化严重影响植物物种多样性。为了解自然、社会经济因素对黑河流域土地利用变化影响下植物物种多样性的变化趋势,本研究使用Dyna-CLUE模型,预测2050年土地利用变化,揭示多因素影响下黑河流域土地利用变化,及土地利用变化与草本、灌木物种多样性间的关系。结果表明:降水、GDP、与自然村距离等因子共同驱动土地利用变化,2050年林地、草地和水域面积的增加和未利用地面积的减小,提高了灌木、草本植物的多样性,并使之均匀度更高,种间优势度减小。耕地面积的扩张和耕地集约化导致植物分布不均、多样性减少。将模拟结果和植物物种多样性发展趋势相结合能够对未来的土地利用规划、政策及生态保护决策提供依据。应针对不同区域土地利用变化情况,制定相应的生物多样性和生态环境保护政策,促进黑河流域生态环境的恢复并支持流域可持续发展。     

淮南矿区谢桥矿A组煤底板灰岩组分结构及水化学特征分析

A组煤(1煤)是矿井延伸开采的主要煤层,受底板承压岩溶水威胁。随着开采深度的增加,A组煤层底板灰岩突水几率也随之逐渐增大。采集谢桥矿A组煤层底板石炭系太原组石灰岩样品及对应层位的太灰水样品,并对不同层石灰岩样品进行显微镜下、X射线衍射(XRD)以及X射线荧光光谱(XRF)分析,对水样进行常规离子组分的测试分析,探讨了A组煤石灰岩矿物组成、化学组分及离子含量之间的关系。研究结果表明:太原组C2Ⅰ层和C2Ⅲ层石灰岩孔隙发育,溶蚀能力强,为含水层;C2Ⅱ层石灰岩裂隙不发育,岩溶不发育,为相对隔水层;太灰水中Ca2+、Mg2+、Na+、K+含量主要与石灰岩组成、pH值以及阳离子交换作用有关;Cl-含量与沉积水体盐度相一致。将岩石的矿物学特征与地下水化学组成同时进行研究对A组煤开采可行性分析具有重要现实意义。     

Survey of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons in Jiaxing city, China

Polycyclic aromatic hydrocarbon (PAH) and nitrated PAH (NPAH) products are toxic. Thus, determination of their concentrations is of great interest to researchers of soil and water pollution control. In this work, soil samples, surface water samples, and groundwater samples were collected, and the concentrations of 16 priority PAHs and 15 NPAHs were determined using an HPLC-ultraviolet detector. Results showed that the total PAH concentrations ranged within 489.69–1,670.11 ng/g (average = 905.89 ng/g) in soil samples, 4.00–23.4 μg/l (average = 9.84 μg/l) in surface water samples, and 2.14–22.3 μg/l (average = 8.37 μg/l) in groundwater samples. The NPAH concentrations were one to two orders of magnitude lower than the PAH concentrations and ranged within 22.72–128.70 ng/g (average = 63.88 ng/g) in soil samples. 2-Nitropyrene and 6-nitrochrysene were the most abundant compounds, accounting for about 14.3 and 26.5 %, respectively. Source analysis revealed that most PAHs originated from coal combustion around the study area, whereas NPAH studies suggested that the primary emission of gasoline engines and daytime OH reactions were the dominant sources of these compounds.     

大电流密度下阴极产物膜的探讨

在室内和现场不同大电流密度下形成阴极产物膜，通过观察膜的形貌、厚度、强度、分析成份，对其进行电位衰变试验、阴极极化试验、生锈试验及维持保护电流试验，进行分析比较，同时对涂层和阴极保护联合防腐时涂层破损、剥落处阴极产物膜的形成，及其对电流密度、保护电位的影响作了探讨。本文还对阴极产物膜的应用价值，以及在阴极保护中应用的可能性作了阐述。     

中国北方现代粟、黍及其野生近缘种的淀粉粒形态数据分析

对来自中国北方不同区域的9个粟（Setaria italica）样品及其野生祖本青狗尾草（Setaria viridis）的7个样品,9个黍（Panicum miliaceum）样品及其近缘野生种糠稷（Panicum bisulcatum）和野黍（Eriochloa villosa）样本各 1个,共27个样品进行了淀粉粒分析。针对每个样品,统计100～200颗淀粉粒粒径数据,100颗形态特征数据,在此基础上初步明确了5种植物淀粉粒如下判别特征: 1）5种淀粉粒中,除野黍淀粉粒为小粒径（X=4.8±0.8μm）的椭球形和球形外,其余4种淀粉粒都以多面体为主,球形或近球形为辅,脐点居中开放,黍、粟、青狗尾草和糠稷淀粉的平均粒径分别为X=7.3±1.4μm,X=9.9±2.3μm,X=7.7±1.4μm和X=6.9±1.2μm。2）粒径大于12μm的淀粉粒一般不是黍的淀粉粒。3）粒径大于14μm的淀粉粒99.9％来自粟。3）粒径小于11μm的淀粉粒,如果超过40％的淀粉粒表面无裂隙,极有可能为黍属的淀粉粒;  如果有超过30％的淀粉粒表面具有裂隙,则非常有可能来自狗尾草属。4）近乎45％的粟淀粉粒粒径处于11～14μm,而只有约4％的青狗尾草淀粉粒粒径位于这一区间。如果粒径在11～14μm的淀粉粒含量超过获得淀粉粒总量的4％,则其中很可能包含有粟的淀粉粒。以上标准在鉴定时还需要综合考虑。高粱（Sorghum bicolor）与薏米（Coix chinensis）在粒径和形态上与狗尾草属和黍属有部分重合,但大部分高粱的淀粉粒具有层纹,薏米则有30％的粒径大于14μm,与粟只有5％的淀粉粒位于这一粒径范围有很大的区别。通过研究发现,在现阶段,典型黍亚科（Panicoideae）种类淀粉形态在统计上的区别是明显的,但仅依靠少量颗粒特征进行区分是困难的,如何把现代淀粉特征准确应用到考古样品的鉴定中,还有待更多的淀粉埋藏学研究。目前,针对粟、黍及其野生近缘种的鉴别,植硅体分析的效果明显好于淀粉粒分析。     

机载19管多星体拖曳式焰弹催化系统

北方大范围层状云和混合云飞机人工增雨(雪)是解除干旱、森林灭火、改善生态环境的重要途径之一。研制的L-1型机载19管多星体拖曳式焰弹催化系统可满足上述需求。该系统由多星体焰弹弹体、AgI焰剂、发射装置和电控装置构成。试验和初步应用证明,该系统工艺稳定、操作简便、发射成功率100%,催化剂成核率在-8℃时高达1015个/g,入云5 min内90%的核即可活化,携弹量760枚,可连续作业4 h以上,后向发射,作业方式灵活。与目前使用的龙B-2型焰弹催化系统相比,该系统是一种新型优越的催化系统。     

盐浴法红宝石离子扩散优化处理研究

采用盐浴法,对红宝石进行离子热扩散处理,应用XL-30 ESEM型扫描电镜与phoenix能谱仪,对样品进行了形貌和元素测试,分析了盐浴法红宝石离子扩散处理的机理,为红宝石热扩散处理提供一种更好的方法。     

利用混合语言编程研制测量数据处理程序

FORTRAN适合于编制数值计算程序 ,但不易于编制菜单等用户界面。 VisualBasic的特点恰恰是易于编制用户界面。因此 Visual Basic和 FORTRAN的混合编程是许多程序员所关注的问题。本文详细介绍了如何用 Visual Basic和 FORTRAN混合编程研制测量数据处理程序 ,并以算例的形式给出了 WGS84坐标系下地心坐标转换到大地坐标 (XYZ→BLH)直接算法的源程序。     

Detecting water yield variability due to the small proportional land use and land cover changes in a watershed on the Loess Plateau,China

Soil conservation practices have been widely implemented on the Loess Plateau to reduce severe soil erosion in north‐central China over the past three decades. However, the hydrologic impacts of these practices are not well documented and understood. The objective of this study was to examine how water yield has changed after implementing soil conservation practices that resulted in changes in land use and land cover in a small agriculture‐dominated watershed, the LuErGou Watershed in Tianshui City, Gansu Province, China. We collected 23 years of hydro‐meteorological data along with three land use surveys of 1982, 1989, and 2000. The land use survey in 2000 suggested that the soil conservation efforts resulted in a 16·6%, 4%, and 16% increase in area of grassland, forested land, and terraces respectively over the two periods from 1982 to 1988 (baseline) and 1989 to 2003 (soil conservation measures implemented). Rainfall–runoff regression models developed for both time periods at the annual and monthly time steps were used to examine the significance of change in water yield in the second time period. The averaged annual run‐off coefficient over 1989–2003 did not change significantly (at the α = 0·05 level) as compared to that in the period 1982–1988. However, we found that soil conservation practices that included re‐vegetation and terracing reduced water yield during wet periods. This study highlights the importance of the precipitation regime in regulating hydrologic effects of soil conservation measures in a semi‐arid environment. We concluded that adequately evaluating the effects of land use change and soil conservation measures on water yield must consider the climatic variability under an arid environment. Copyright © 2009 John Wiley & Sons, Ltd.     

A search for double-peaked narrow emission line galaxies and AGNs in the LAMOST DR1

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST) has released more than two million spectra,which provide the opportunity to search for double-peaked narrow emission line(NEL) galaxies and active galactic nuclei(AGNs).The double-peaked narrow-line profiles can be well modeled by two velocity components,respectively blueshifted and redshifted with respect to the systemic recession velocity.This paper presents 20 double-peaked NEL galaxies and AGNs found from LAMOST DR1 using a search method based on a multi-Gaussian fit of the narrow emission lines.Among them,ten have already been published by other authors,either listed as genuine double-peaked NEL objects or as asymmetric NEL objects,and the remaining ten are original discoveries.We discuss some possible origins for the double-peaked narrow-line features,such as interaction between jet and narrow line regions,interaction with companion galaxies,and black hole binaries.Spatially resolved optical imaging and/or follow-up observations in other spectral bands are needed to further discuss the physical mechanisms at work.